Greetings,

I Like my M16 direct-impingement 11.5" upper generally, although it gives
quite a blast of gas in the face when shooting suppressed.
(and before anyone asks, yes, I have a "gas buster" charging handle
installed, which helps only a little).

This issue has caused me to think again about maybe getting a piston upper
to run on it.

Any suggestions in this regard?   Possibilities I've seen include the HK416
upper and some offerings from LWRC.

Thanks for your input,

SD

Any piston upper should work in an M16 or AR conversion, provided you have the correct bolt carrier.

The usual concern with piston systems that don't have something like the internal rails of the 416 types, is carrier tilt, which can put wear on your receiver extension and possibly your expensive full auto lower - though there are also various fixes to mitigate or eliminate tilt.

HK416 upper is nice but overpriced. Investment Grade Firearms can convert a MR556 upper to enable full auto but you still don't get adjustable gas.

For my "HK416" fix I bought a POF 416 10.5" upper. 3 position gas selector: normal, suppressed, off.



Much less gas to the face. Only drawback is that most suppressor mounts will be too wide to remove the gas selector for cleaning without removing the suppressor mount. See the minimal clearance for the gas plug to be removed with the factory muzzle brake in the pic.

For your carrier tilt concerns, POF makes an anti-tilt buffer tube.

I would suggest sticking with your DI upper and getting an adjustable gas block instead. You can tune the gas system to where there's very little gas in your face. But yeah the Gas Buster charging handle is also a good start. I also like to run heavier buffers as well. Maybe pick up a H3 buffer or 9mm buffer. Of course also keep in mind no matter what kind of upper you run your'e always going to get some gas in the face, it's just the nature of suppressors in general. But I personally find my DI uppers to be quieter than my piston uppers.

Thanks for the replies thus far.  Did some more quick searching and found a chart showing "proper" ejection (see below).

Based on my shooting range video, I'm ejecting in the 1-2:00 zone, which is overgassed.

So I'll probably order the H3 buffer; also, I was using the M42K suppressor.  I have an SDN6
also, and I'm going to bet that using it will cause a bit less back pressure.

Again, thanks for all the responses.

I run the Adams Arms Kit. Have had it a few years on and it has been flawless.

http://slrrifleworks.com/index.php?route=product/product&path=57&product_id=496

I put that on my Suppressed 10.5" and I now have no issue with gas in the face. Also, since there is less gas i changed to a V7 Titanium BCG instead of steel and went from a H2 to an H1 buffer, runs just as reliably and i reduced the weight of my rifle by like 6+ oz. Adjustable gas blocks are def the way to go.

IMO piston uppers just add weight and extra parts to deal with.

I have an LWRC 10.5 with adjustable gas. The adjustment knob is easily reached and it's tuned to be either suppressed or not. Easy operation, and it has performed flawlessly in semi and full auto. If I had to do it over again, I would purchase the same upper.

Me too.  I get hammered on M4C for saying it though.  Several years ago, Midsouth had the Adams retrofit kits on sale for like half price.  I built an upper with a gray Colt flat-top to match my 9m-serial-number Colt lower, Noveske 10.5" polygonal, and the AA retrofit kit complete with bolt carrier.  It runs great.  It's cool and clean.  I hardly ever have to clean it.  It doesn't get nearly as hot as the DI systems that I'd used before.  I do get a bit of wear in the buffer tube, but I feel that as long as I keep an eye on it and replace the tube every few years, my Colt lower will be just fine.

Aside from the carrier tilt issue, one more thing may make you re-think using a piston and a suppressor:  To the shooter's ears, the piston system is louder with a can than a DI system.  I believe this is because most of the noise from a DI gun comes out the vent holes in the carrier - out the right side of the gun, and away from a right-handed shooter's ears.  But with the piston system, the venting is right in front of you, at the gas block.  So it doesn't sound as quiet to the shooter as the DI does.

But  that's a small price to pay for all that cool, clean, hassle-free shooting.

My buddy has one of these and also a 10.5 Mk416 upper and both are great.

I just picked up a adams arms 545x39mm cant wait to chop it and bang xxxxxxx!

I do also. Many thousands through it and 100% with and without can.  Mine is M6A3 10.5"

 
I have a 10.5" M6A2 that has always run as expected. The only thing I would change is I would have gotten it with the adjustable gas.

I don't think you'll put NEAR the amount of rounds through them than Battlefield Vegas does, but the guy that runs it says the only piston uppers that survived non stop full auto are the HK and TDI (Titan Defense 415) 416 uppers.



Everything else failed.

I run the Noveske SwitchBlock on my RR.  I like it a lot.

Adams arms piston kit on a 7.5" barrel.  Runs great, only downside is piston guns are heavy bastards.  I get no gas in the face.

I have a factory adams arms 545x39 piston upper i have to change out the buffer in the m16 lower?

Just wanted to f/u on my earlier thread with some info on various options I have since tried, for reducing gas
blowback in an M16 running FA suppressed--

#1.  GemTech suppressed bolt carrier


#2.  Adams Arms 556 Carbine Tactical EVO 11.5" Evolution Piston Upper



Of course, all the low-profile/lightweight/PDW uppers get hot fast under full-auto fire... I may
have to next find a good "range upper" to mitigate this, as much as possible.

Anyone running the "Dissipator" style uppers on an M16?

(e.g.,  http://www.midwayusa.com/product/683909/bushmaster-ar-15-dissipator-a3-upper-receiver-assembly-556x45mm-nato-16-barrel)

I still highly recommend you try an adjustable gas block. It should solve all of your issues without adding weight to the firearm and allowing you to use all milspec style parts including high end after market parts.

Thank you for taking the time to respond to my post - good info!

Could someone send / post a link to a recommended adjustable gas block upper that I can just Purchase?
(don't want to build one myself right now)

And yeah-- looking like I'm going to end up getting a more traditional upper for
range use / "kind of" high volume fire.  (and don't you just love the modularity
of the M16 system?! )

http://slrrifleworks.com/index.php?route=product/product&path=57_125&product_id=496
That's what I use on mine